US20060122646A1 - Daisy design for occlusion device - Google Patents

Abstract

The present invention is an occlusion device having a collapsible frame which allows the occlusion device to be more easily centered in a defect and retrieved in situ. The occlusion device comprises a first post configured to be located on a first side of a defect, a second post configured to be located on a second side of the defect, and a fixation device connected to the first and second posts. The fixation device is used to hold the occlusion device in place across a defect, and comprises several segments. The segments are shaped so that each segment comprises a loop, causing the fixation device to resemble a “daisy design.”

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)
• None.
BACKGROUND OF THE INVENTION
• This invention relates to an occlusion device for the closure of physical apertures, such as vascular or septal apertures. More specifically, this invention relates to an occlusion device that self-centers across a defect and can be retrieved and redeployed in situ.
• The heart is generally comprised of four chambers: the left and right atrium and the left and right ventricle. Separating the left and right sides of the heart are two walls, or septa. The wall between the two atria is the interatrial septum, and the wall between the two ventricles is the interventricular septum. There are several defects which can affect the septa of both children and adults, including patent ductus arteriosus, patent foramen ovale, atrial septal defects (ASDs), and ventricular septal defects (VSDs). Although the causes and physical characteristics of these defects vary by type, these defects may generally comprise an aperture, flap, or hole in the septum which allows blood to shunt between chambers in the heart where there is no blood flow in a normal, healthy heart. This abnormal blood flow can cause a variety of health problems.
• Normally, permanently repairing certain cardiac defects in adults and children requires open heart surgery, which is a risky, painful, and expensive procedure. Surgically closing an aperture in the heart requires the patient to undergo general anesthesia and requires opening of the chest cavity. The patient may spend several days in the hospital and may take several weeks to recover before being able to return to normal levels of activity.
• To avoid the risks and discomfort associated with open heart surgery, modern occlusion devices have been developed that are small, implantable devices capable of being delivered to the heart through a catheter. Rather than surgery, a catheter inserted into a major blood vessel, and an occlusion device is moved through the catheter to the treatment site where it can then be deployed at the defect. This procedure is performed in a cardiac cathlab, and avoids the risks, pain, and long recovery associated with open heart surgery.
• There are currently several types of occlusion devices capable of being inserted via a catheter including, button devices, collapsible umbrella-like structures, and plug-like devices. These modern occlusion devices can repair a wide range of cardiac defects, including patent foramen ovale, patent ductus arteriosus, atrial septal defects, ventricular septal defects, and may occlude other cardiac and non-cardiac apertures.
• One form of occlusion device generally has a first side, a second side, and a center section. Once the occluder is deployed, the first side is positioned on one side of the aperture to be occluded, and the second side sits in the other side of the aperture. The occluder's center section extends through the center of the defect or aperture being occluded. The left and right sides occlude the aperture on the respective sides of the aperture. Because the center section of the occlusion device may be small relative to the size of the aperture to be occluded, it is a challenge to ensure the occlusion device is properly centered across the aperture.
• Further, the size of defects varies from patient to patient, with some defects being larger than others. If the defect is large, it is desired that the center section of the occluder remain in the center of the defect so that the first and second sides of the occluder are optimally positioned to occlude the entire defect. If the center section not optimally centered, the first and second sides of the occluder may not be optimally placed so that the defect is properly occluded. If the defect is not properly occluded, blood may continue to shunt through the defect lessening the effectiveness of the occluder.
• Many occluders are designed so that the first and second sides are collapsible, allowing the occluder to fit inside a catheter. When in the collapsed position, it is desired that the occluder be highly compact so that the smallest diameter catheter may be used when deploying the occluder. A catheter with a smaller diameter reduces trauma, improves maneuverability, and allows the device to be used in patients who have small vasculature or who are very young. Loading the device into a small diameter catheter must be done by hand, requires a high degree of manual dexterity, and can be time consuming.
• Once the device is loaded, it is maneuvered through the catheter to the treatment site within the body, where it is then deployed. In the event the device is not optimally deployed, it may be retrieved, and the procedure may be performed again. While some types of occlusion devices are retrievable via catheter, many require open heart surgery to be retrieved.
• Even in instances where the device can be retrieved using a catheter, retrieval may require insertion of a larger diameter catheter than that used for insertion. A larger diameter catheter may be required because the device may not readily resume the compact shape it had before deployment. Once retrieved, the device may be compromised from the stress of withdrawing it back into the catheter, even if a larger diameter catheter has been used. As such, it may not be possible to reuse the retrieved occlusion device.
• In addition, devices retrieved via catheter are typically not properly loaded for redeployment. Thus, even if the device is retrievable, the device must be pulled back through the catheter and be completely removed from the catheter so that it can be properly reloaded. Reloading is time consuming, additional time to the procedure, and creates wear and tear on the device. Often, the retrieved device cannot be reused because it has been damaged by the retrieval process. If the device cannot be reused, a new device is required, which increases the cost of the procedure.
• Thus, there is a need in the art for an occlusion device that is easily loaded into a catheter, and that can be retrieved, reloaded, and redeployed in situ. There is also a need in the art for an occlusion device which has a centering system to improve the ability of the device to be centered in the defect.
BRIEF SUMMARY OF THE INVENTION
• The present invention relates to an occlusion device which can be more easily centered in a defect, and which is capable of being retrieved in situ. The occlusion device comprises a first post configured to be located on a first side of a defect, a second post configured to be located on a second side of the defect, and a fixation device connected to the first and second posts. The fixation device is used to hold the occlusion device in place across a defect, and comprises several segments. The segments are shaped so that each segment comprises a loop, causing the fixation device to resemble a “daisy.”
• More specifically, proximate to the loop on each segment is a first radial portion extending from the first post to the loop and a second radial portion extending from the loop to the second post. When the device is deployed, the first post and the first radial portions of the segments are located on a first side of the defect. Similarly, the second post and the second radial portions of the segments are located on a second side of the defect. The loop portions of the segments extend through the defect and help to center the occlusion device in defect.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a top perspective view of an occlusion device illustrating features of the present invention.
• FIG. 2 is a bottom perspective view of an occlusion device illustrating features of the present invention.
• FIG. 3 is a top plan view of the occlusion device.
• FIG. 4 is an exploded perspective view of the fixation device of the occlusion device.
• FIGS. 5A-5C illustrates the occlusion device as it is collapsed to be loaded into a catheter.
• FIGS. 6A-6B are side perspective views of the occlusion device implanted in a septal aperture.
DETAILED DESCRIPTION
• FIG. 1 is a top perspective view ofocclusion device10 suitable for occluding an aperture in the body, such as a cardiac defect.Occlusion device10 comprises first post orhub12,fixation device14, first occludingsheet16, andsecond occluding sheet18.Fixation device14 is connected tofirst post12, andfirst sheet16 is attached tofixation device14.First sheet16 can be attached tofixation device14 using any suitable mechanism, such as a plurality ofsutures20. Also visible iscatheter22, which may be used to deployocclusion device10.
• FIG. 2 is a bottom perspective view ofocclusion device10. More visible in the bottom perspective view issecond sheet18. Also visible isfixation device14, second post orhub24,delivery device26, andcatheter22.Fixation device14 also connects tosecond post24, similar to theway fixation device14 connects tofirst post12. Also, similar tofirst sheet16,second sheet18 is connected tofixation device14 using any suitable method, such as sutures20.
• Occlusion device10 is constructed so that it can be deformed or collapsed and placed intocatheter22. To allowocclusion device10 to be collapsed for placement intocatheter22,fixation device14 is designed to be deformable from the starting configuration illustrated inFIGS. 1-2. First andsecond sheets16,18 attached tofixation device14 are also flexible, and are configured to fold asfixation device14 is collapsed. The manner in whichocclusion device10 can be collapsed so that it can be deployed throughcatheter22 is described in greater detail below with reference toFIGS. 5A-6B.
• Occlusion device10 is connected todelivery device26, preferably atsecond post24.Delivery device26 connects toocclusion device10 in any suitable manner, such as by a threaded connection or using any suitable form of forceps.Delivery device26 is used to holdocclusion device10, such as whenocclusion device10 is being loaded intocatheter22,occlusion device10 is being moved throughcatheter22, or whenocclusion device10 is being deployed at a defect.
• Whenocclusion device10 is deployed,sheets16,18 are positioned on opposing sides of the defect and serve to occlude the defect.Fixation device14 is used to holdocclusion device10 in place, and to urgesheets16,18 against the tissue adjacent the defect being occluded.Sheets16,18 are preferably connected toocclusion device10 so thatsheets16,18 are located on the inside offixation device14. However,occlusion device10 is not so limited, andsheets16,18 may be attached at any location as desired or suitable.
• Sheets16,18 may be any suitable material, and preferably are comprised of a medical grade polymer in the form of film, foam, gel, or a combination thereof. One suitable material is a high density polyvinyl alcohol (PVA) foam, such as that offered under the trademark IVALON®. To minimize the chance ofocclusion device10 causing a blood clot,foam sheets16,18 may be treated with a thrombosis inhibiting material. One such suitable material is heparin.
• To ensure there is sufficient tension to holdsheets16,18 in place,fixation device14 is made of a suitable material, such as metal wire. More preferably,fixation device14 is formed of a material capable of shape memory. One suitable material is a nickel-titanium alloy, commonly called Nitinol. Nitinol is preferably used because it is commercially available, very elastic, non-corrosive and has a fatigue life greater than that of stainless steel.Fixation device14 may also be heat treated to increase shape memory. To further ensure thatfixation device14 is sufficiently durable and does not suffer from fatigue failure, one embodiment of the present invention comprises makingfixation device14 of stranded wire or cables.
• Fixation device14 comprises six individual portions, orarms28. However,occlusion device10 is not so limited.Occlusion device10 may comprise any suitable number ofarms28. Further, the exact shape offixation device14 can be varied based on the desired characteristics offixation device14, such as the amount of tension required to holdocclusion device10 in place across the defect, or the ability ofocclusion device10 to self center in a defect. As such,occlusion device10 may be formed offewer arms28, such as four, ormore arms28, such as eight, or ten as long asfixation device14 is capable of maintaining the position ofocclusion device10.
• Preferably,fixation device14 is designed witharms28 arranged symmetrically aboutcenter post12,24 so that the angles between eachadjacent arm28 are about equal. Placingfixation device14 symmetrically aboutcenter post12,24 is preferable because it ensures thatfixation device14 more evenly applies pressure against the tissueproximate occlusion device10 when it is in place. When formed of sixarms28, eacharm28 may be separated fromadjacent arm28 by approximately 60 degrees. However, the invention is not so limited, andarms28 may be arranged at any angles desired or suitable.
• FIG. 3 is a top plan view ofocclusion device10 more clearly illustrating the design offixation device14. As can be seen inFIG. 3, eacharm28 ofwire fixation device14 is shaped so that it comprises aloop30. Because of the shape ofarms28, theloops30 resemble a flower shape having several petals, or a “daisy design.” Relative to centerpost12, eachloop30 has aproximal side32 and adistal side34. An effectiveinner diameter38, indicated by dashedline38, is formed byproximal sides32 of eachloop30. Similarly,distal sides34 ofloops30 correspond toouter diameter40 ofocclusion device10. Eacharm28 is essentially a one-turn spring, and comprisesloop30, firstradial portion42, and secondradial portion44. When inserted in a defect, firstradial portion42 is designed to be placed on one side of the defect and secondradial portion44 is placed on the opposite side of the defect. Between firstradial portion42 and secondradial portion44 isloop30. When deployed,loop30 extends through the defect and helps to centerocclusion device10 in the defect. Previous devices typically utilized two occluding bodies connected by a center post, with the center post extending through the defect. Such devices are difficult to center in the defect because the center post often has a diameter much smaller than the size of the defect. Thus, when placed across a defect, the center post has minimal ability to center the device in the defect. Instead, the device must be carefully deployed to ensure it is centered.
• In contrast,occlusion device10 is designed to be self centering. The self centering feature is due toocclusion device10 having a much larger effective center created byinner diameter38. One or more ofproximal sides32 ofloops30 may contact the tissue at the perimeter of the defect. In doing so,loops30 help arrangeocclusion device10 in the defect so that it is more effectively centered.
• Inner diameter38 andouter diameter40 can be used to accurately select the size ofocclusion device10 which best fits the defect to be occluded. More specifically, when selecting theappropriate occlusion device10 to occlude a defect, a decision can be made as to the appropriate size ofocclusion device10 by correlating effectiveinner diameter38 created byproximal sides32 ofloops30, or effectiveouter diameter40 created bydistal sides34 ofloops30, or possibly both, to the size of the defect.
• FIG. 4 is an exploded view of an occlusion device illustrating one manner of formingocclusion device10. Shown inFIG. 4 isfirst center post50,second center post52, and threefixation members53,54,55.First post50 comprisesfirst hole56,second hole58, andthird hole60. Similarly,second post52 comprisesfirst hole62,second hole64, andthird hole66.Second post52 further comprisesknob68 located at one end.
• In the embodiment illustrated inFIG. 4, eachwire fixation member53,54,55, comprises twoloop portions70. Between twoportions70 iscenter section72. Because each offixation members52,53,54, are formed of a single wire, the two ends74 of the wire meet atcenter section72. Also shown are twosheets76,78, which are attached tofixation members52,53,54 in any suitable manner, as described above.
• One method of assemblingfixation device14 is to connect eachfixation member53,54,55, to first andsecond center post50,52 at the holes56-66. One suitable way to do so is to threadfirst fixation member53 throughtop hole60 offirst post50 untilcenter section72 offixation member53 is located about athole60. Similarly,second fixation member54 is inserted intosecond hole58 so thatcenter section72 offixation member54 is located athole58 infirst center post50. Finally,third fixation member55 is inserted intothird hole56 offirst center post50 so thatfirst center post50 is located nearcenter section72 ofthird fixation member55.
• Similarly, ends74 offirst fixation member53 are connected tosecond post50 atthird hole66. Likewise, ends74 ofsecond fixation member54 are connected tosecond center post52 atsecond hole64, and ends74 ofthird fixation member55 are connected atthird hole62.
• When connectingmembers53,54,55 to first and second center posts50,52, any suitable method may be used. For instance,members53,54,55 may be welded, crimped, adhered, or otherwise connected to centerposts50,52. Alternately,fixation members53,54,55 may simply be inserted holes56-66 on first andsecond posts50,52. Further, although eachfixation member53,54,55 is shown as formed from a single wire, the invention is not so limited. Each arm may be formed of a separate length of wire, and may be connected to centerposts50,52 in any suitable manner.
• To ensure that each fixation member is arranged so that it is radially separated from an adjacent fixation member by approximately 60 degrees, holes56-66, may be formed in center posts50,52 at various angles to each other. Further, to ensure thepost50,52, retain the strength required, yet remains small, holes56-66 may be arranged vertically along theposts50,52 so that when the holes are drilled, center posts50,52 remain structurally sound. The arrangement of holes56-66 on center posts50,52 further ensures that when the occlusion device is collapsed for insertion into a catheter, any overlapping ofwire fixation members53,54,55 is minimized. Minimizing the overlapping offixation members53,54,55, particularly near center posts50,52, helps decrease the overall bulk of the occlusion device, and allows for the use of small diameter catheters.
• FIGS. 5A-5C illustrate one advantage of the occlusion device of the present invention. In deploying an occlusion device, it is preferred that the occlusion device be collapsible to fit within a small diameter catheter, with the smallest diameter catheter possible being preferred. Furthermore, it is desired that the occlusion device be easily loaded into the catheter. Finally, once an occlusion device has been deployed in a defect, it is desired that the occlusion device be easily retrievable should it be placed at a less than optimal location across the defect. Due to the design of the fixation device, the present invention is easily loaded into small diameter catheters and is also easily retrievable in situ.
• Shown inFIG. 5A, iscatheter90, graspingdevice92, and occlusion device94. Occlusion device94 comprisesfirst center post96, and centersecond post98. As described above, connected between first and second center posts96,98 isfixation device100. Attached tofixation device100 isfirst sheet102 andsecond sheet104.Fixation device100 corresponds to the daisy design described above, and is formed ofindividual fixation segments106 which, in their undeformed states, comprise a loop between two radial portions, as illustrated and described above.
• As viewed inFIG. 5A,fixation device100 comprisesmiddle section108 located between first andsecond sheets102,104.Middle section108 corresponds to the location of loop portions (illustrated above with reference toFIGS. 1-4) offixation device100.
• To allow occlusion device94 to be inserted intocatheter90, occlusion device94 must be collapsed or folded. To do so,first center post96 is pulled away fromsecond post98. Upon doing so,fixation device100 begins to deform, withindividual fixation segments106 beginning to straighten. More specifically, as illustrated inFIG. 5A, asfirst center post96 is pulled apart fromsecond center post98, each loop offixation segments106 begins to uncoil. At the same time, first andsecond sheets102,104 begin to fold.
• FIG. 5B illustrates occlusion device94 asfirst center post96 continues to be pulled away fromsecond center post98.Middle section108 offixation device100 further uncoils, andfixation members106 straighten even more. Similarly, first andsecond sheets102,104 become more folded asfixation members106contact sheets102,104 and asfixation members106 uncoil and straighten.
• In one embodiment,sheets102,104 are attached to wirefixation device100 so that aswire fixation device100 collapses,sheets102,104 remain on the inside offixation device100. This increases the durability of occlusion device94 as it is loaded intocatheter90. More specifically, as occlusion device94 is withdrawn intocatheter90,fixation device100 is the first part of occlusion device94 to contact edges ofcatheter90 as it is loaded. Becausefixation device100 is preferably formed of wire, it is more robust thansheets102,104. Ensuring that it iswire fixation device100 which contacts the catheter first minimizes potential damage tosheets102,104. This design also reduces the chance thatsheets102,104 may become separated fromfixation device100 or damaged bycatheter90 as they are pulled into it.
• As can be seen inFIG. 5B, it is possible to ensure thatsecond sheet104 is connected tosecond post98, as well as connected to wirefixation device100. However, occlusion device94 is not so limited. Alternately, as illustrated withfirst sheet102, it is not necessary to suturesheet102 to centerpost96. However, suturing eithersheet102,104 to centerpost96,98 may be desirable because the suturing helps to holdsheets102,104 in place as desired during loading and unloading and after occlusion device94 has been deployed across a defect.
• FIG. 5C provides an illustration of occlusion device94 once it has been collapsed for insertion intocatheter90. Given the design offixation device100, when fully collapsed, occlusion device94 is capable of fitting into a verysmall diameter catheter90. Because the loops offixation members106 are fully uncoiled, the bulk created bywire fixation device100 is greatly minimized when in the collapsed position. Further, as described above, placement offixation members106 along center posts96,98, as well as howfixation members106 are connected to centerposts96,98, further serves to reduce the bulk of occlusion device94 when it is in the collapsed position.
• More specifically, staggering the placement offixation members106 along the length of center posts96,98 serves to prevent all offixation members106 folding at one location along center posts96,98. Similarly, varying the angles at whichfixation members106 are inserted into center posts96,98 further serves to reduce the bulk of occlusion device94 whenfixation members106 fold at center posts96,98 areas. The bulkiest portion of fixation device94 becomes the area where first andsecond sheets102,104 are folded. As a result, the size ofcatheter90 can be greatly reduced.
• In previous devices, the occlusion device may comprise several wire arms emanating from a center post. The ends of the wire arms were often capped with atraumatic tips to minimize damage to tissue contacted by the wire arms. When inserting such an occlusion device into a catheter and the arms were folded in the axial direction along the center post, the tips often overlapped. This caused increased bulk on the device at the location of the atraumatic tips when the device was folded for insertion into a catheter. As a result of this increased bulk, a larger catheter was required. In contrast, the present invention does not require the use of atraumatic tips at the ends of the arms, and thus does not experience the same challenges in ensuring the tips do not form a cluster when the arms are folded. As a result, the device is less bulky and can be used with a smaller diameter catheter.
• Another challenge for previous occlusion devices formed of several wire arms emanating from a center post related to the high degree of manual dexterity required for loading the devices into the catheter. For instance, to insert such an occlusion device into a catheter, a first set of wire arms must be folded in one direction, while at the same time a second set of arms is folded in the opposite direction. Loading the occlusion device into a catheter while ensuring the arms are properly folded in the correct directions often proves difficult.
• In contrast, the present invention is readily inserted into a catheter. The device can be grasped at the end posts using any suitable method, such as by using a delivery device to grasp one end post and a user's fingertips to grasp the other end post. By simply pulling the two grasped posts away from each other, the device is readily collapsed for easy loading into the catheter.
• Not only is the ability of loading the new occlusion device into a catheter improved, but also the design of the fixation device of the present invention makes the device easily retrievable. Should a user feel that one or both sides of the occlusion device are not optimally seated at the defect, either side of the occlusion device can be easily retrieved by simply pulling it back into the catheter, and forcing the device to collapse as described above with reference toFIGS. 5A-5C.
• Another advantage of the present invention is that once retrieved, due to the manner in which the fixation device collapses the device, the occlusion device is properly loaded in the catheter, and thus is readily available for re-deployment in situ. Once again, both sides have this unique feature. Thus, if it is necessary to reposition either side, or the entire device, both sides are easily retrievable, and once retrieved, are properly loaded for another attempt at deployment.
• Other previous occlusion devices are formed of a wire mesh material. The large amount of metal required to form the device has certain disadvantages. For instance, the metal structure may eventually suffer fatigue and break, requiring removal or replacement of the device. The present invention achieves the ability to fit into a small diameter catheter while still minimizing the amount of metal wires needed to form the fixation device.
• FIGS. 6A and 6B illustrate an occlusion device as it is deployed across a defect. Shown inFIG. 6A is a portion ofseptal wall110 havingseptal aperture112.Occlusion device114 is shown being deployed acrossseptal aperture112. Similar to the occlusion devices described above,occlusion device114 comprisescatheter115,first center post116,second center post118,fixation device120,first sheet122, andsecond sheet124.Fixation device120 comprisesfirst arm portions126 on afirst side130 of a defect, andsecond arm portions128 on asecond side132 of a defect.
• To insert theocclusion device114 acrossseptal aperature112,catheter115 is positionedproximate defect112.Occlusion device114 is advanced throughcatheter115 until afirst arm portions126 ofocclusion device114 exitscatheter115. Once the first side ofocclusion device114 has exitedcatheter115,fixation device120 partially returns to its original shape. In returning to its original shape,first arm portions126 offixation device120 partially return to their looped configuration. The radial portions offirst arm portions126 urgefirst sheet122 againstseptal wall110. In this way,septal aperture112 is blocked on the first side ofseptal wall110.
• Next,second arm portions128 are allowed to exitcatheter115 onsecond side132 ofseptal aperature112. As shown inFIG. 6A, once allowed to exitcatheter115, the second side ofocclusion device114 begins to return to its original shape. To do so,second arm portions128 offixation device120 begin to return to their original shape, and in doing so, begin to unfoldsecond sheet124.
• As shown inFIG. 6B, bothsides126,128 ofocclusion device114 have been deployed.Catheter115 has been withdrawn, along with the grasping device used to holdsecond center post118. Oncefixation device120 has returned to its original shape memory configuration,fixation device120 is arranged so that the first radial portions offirst arm portions126 are located onfirst side130 ofseptal aperature112, and the second radial portions ofsecond arm portions128 are located onsecond side132 ofseptal aperature112.Arm portions126,128 hold first andsecond sheets122,124 againstseptal wall110.
• Loop portions134 are formed as part of first andsecond arm portions126,128.Loop portions134 offixation device120 are arranged acrossseptal aperature112. Becauseloop portions134 offixation device120 pass throughseptal aperature112,loop portions134 may contact portions of the tissue surrounding theseptal aperature112. This contact helps to centerocclusion device114 inseptal aperature112.
• Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims (30)

1. A device for use in occluding an aperture, the device comprising:

a first post;

a second post; and

an arm extending from the first post to the second post comprising a loop.

2. The device ofclaim 1 wherein the arm is a wire formed of nickel titanium.

3. The device ofclaim 1 wherein the arm is formed to have shape memory.

4. The device ofclaim 1 wherein the arm is formed of stranded wire.

5. The device ofclaim 1 wherein the arm further comprises a first radial section extending from the first post to the loop and a second radial section extending from the loop to the second post.

6. The device ofclaim 5 and further comprising a first sheet attached to the device on a first side of the loop and a second sheet attached to the device on a second side of the loop.

7. The device ofclaim 1 wherein the device comprises six arms.

8. An occlusion device for closing an aperture, the occlusion device comprising:

a first post;

a second post; and

a fixation device comprising a plurality of fixation segments, wherein each fixation segment comprises:

a first end connected to the first post,

a second end connected to the second post, and

a loop between the first and second ends.

9. The occlusion device ofclaim 8 wherein each fixation segment further comprises a first radial portion extending from the first post to the loop, and a second radial portion extending from the loop to the second post.

10. The occlusion device ofclaim 8 wherein the first post further comprises a grasping knob.

11. The occlusion device ofclaim 10 and further comprising a first occluding sheet connected to the fixation device.

12. The occlusion device ofclaim 11 and further comprising a second occluding sheet connected to the fixation device, wherein the first sheet is connected to the fixation device on a first side of the loops of the fixation segments and the second sheet is connected to the fixation device on a second side of the loops of the fixation segments.

13. The occlusion device ofclaim 11 wherein the first sheet is connected to the fixation device using sutures at the first radial portions of the fixation segments.

14. The occlusion device ofclaim 12 wherein the first sheet is connected to the fixation device using sutures at the first radial portions of the fixation segments and the second sheet is connected to the fixation device using sutures at the second radial portions of the fixation segments.

15. The occlusion device ofclaim 8 wherein the plurality of fixation segments comprises six arms.

16. The occlusion device ofclaim 8 wherein the plurality of fixation segments are formed of stranded wire.

17. The occlusion device ofclaim 16 wherein each fixation segment has a shape memory.

18. The occlusion device ofclaim 16 wherein the plurality of fixation segments are formed of nickel titanium.

19. The occlusion device ofclaim 8 wherein the plurality of fixation segments are connected to the first post so that each fixation segment is about 60 degrees from an adjacent fixation segment.

20. The occlusion device ofclaim 8 wherein the plurality of fixation segments comprises three wires.

21. The occlusion device ofclaim 8 wherein the first and second posts have holes therein, and the fixation segments are connected to the first and second posts at the holes.

22. The occlusion device ofclaim 21 wherein the holes comprise three holes arranged vertically along each of the first and second posts.

23. An occlusion device, the occlusion device comprising:

a first post;

a second post; and

a collapsible support frame connected between the first and second posts, wherein the support frame comprises a plurality of wire segments, each wire segment including a coil.

24. The occlusion device ofclaim 23 wherein the wire segments are formed of a material having shape memory.

25. The occlusion device ofclaim 23 wherein the wire segments are formed of stranded wire.

26. The occlusion device ofclaim 23 wherein the wire segments are arranged so that each wire segment is about 60 degrees from an adjacent wire segment.

27. The occlusion device ofclaim 23 wherein the wire segments are formed of three wires.

28. The occlusion device ofclaim 27 wherein the collapsible support frame is connected to the first and second posts so that the three wires are arranged vertically along each of the first and second posts.

29. The occlusion device ofclaim 23 and further comprising a first occlusion sheet and a second occlusion sheet connected to the collapsible frame.

30. The occlusion device ofclaim 29 wherein the first occlusion sheet and the second occlusion sheet connected to the collapsible frame using sutures.

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